Java/Java Testing/C++ Exam 2025
Questions and Answers
What is JAVA - ANSWER✔✔-A high-level programming language developed by Sun
Microsystems. Java was originally called OAK, and was designed for handheld devices
and set-top boxes. Oak was unsuccessful so in 1995 Sun changed the name to Java and
modified the language to take advantage of the burgeoning World Wide Web.
What are the basic concepts of object oriented programming? - ANSWER✔✔-Object-
oriented programming (OOP) is a programming language model organized around
objects rather than "actions" and data rather than logic.
Historically, a program has been viewed as a logical procedure that takes input data,
processes it, and produces output data. The programming challenge was seen as how to
write the logic, not how to define the data.
,Object-oriented programming takes the view that what we really care about are the
objects we want to manipulate rather than the logic required to manipulate them.
What is encapsulation? - ANSWER✔✔-The wrapping up of data and functions into a
single unit (called class) is known as encapsulation.
Encapsulation containing and hiding information about an object, such as internal data
structures and code.
Define inheritance? - ANSWER✔✔-Inheritance is the process by which objects of one
class acquire properties of objects of another class.
It allows the extension and reuse of existing code without having to rewrite the code
from scratch.
Define polymorphism? - ANSWER✔✔-Polymorphism simply means "many forms". In
java polymorphism is acheived through method overloading and overriding.
For example, say you have an Animal class and two sub classes called Lion and Cat
class. All animals make a sound, so lets say there is a make sound method in all of these
classes.
,When you call the make sound method from a lion object that is stored in an Animal
reference, it would call the make sound method from the Lion Class. That is how you
would explain polymorphism using overriding.
Define Constructors? - ANSWER✔✔-A constructor is a member method with the same
name as its class. The constructor is invoked whenever an object of its associated class is
created.It is called constructor because it constructs the values of data members of the
class.
What is a Class? - ANSWER✔✔-A class is a blueprint for an object
What is an Object? - ANSWER✔✔-An instance of a class
What is multiple inheritance? - ANSWER✔✔-A class can inherit properties from more
than one class which is known as multiple inheritance.
What are the advantages of inheritance? - ANSWER✔✔-Code reusability
Saves time in program development.
What is the difference between an Array and a List? - ANSWER✔✔-The main difference
between an array and a list is how they internally store the data. whereas Array is
collection of homogeneous elements. List is collection of heterogeneous elements.
, What is an iterator? - ANSWER✔✔-Iterators are like pointers. They are used to access
the elements of containers thus providing a link between algorithms and containers.
Iterators are defined for specific containers and used as arguments to algorithms.
What is this pointer? - ANSWER✔✔-It is a pointer that points to the current object. This
can be used to access the members of the current object with the help of the arrow
operator.
What are pass by reference and passby value? - ANSWER✔✔-Pass By Reference means
the passing the address itself rather than passing the value.
Passby Value means passing a copy of the value to be passed.
What is the Java API? - ANSWER✔✔-What is the Java API?
The Java API is a large collection of ready-made software components that provide
many useful capabilities, such as graphical user interface (GUI) widgets.
What is the Java Virtual Machine (JVM)? - ANSWER✔✔-The Java Virtual Machine is
software that can be ported onto various hardware-based platforms.
What is variables and then types - ANSWER✔✔-Variables is an identifier that denotes a
storage location used to store a data values.unlike constants that remain unchanged
during the execution of a program, a variable may takes different values at different
times during the execution of the program.
Questions and Answers
What is JAVA - ANSWER✔✔-A high-level programming language developed by Sun
Microsystems. Java was originally called OAK, and was designed for handheld devices
and set-top boxes. Oak was unsuccessful so in 1995 Sun changed the name to Java and
modified the language to take advantage of the burgeoning World Wide Web.
What are the basic concepts of object oriented programming? - ANSWER✔✔-Object-
oriented programming (OOP) is a programming language model organized around
objects rather than "actions" and data rather than logic.
Historically, a program has been viewed as a logical procedure that takes input data,
processes it, and produces output data. The programming challenge was seen as how to
write the logic, not how to define the data.
,Object-oriented programming takes the view that what we really care about are the
objects we want to manipulate rather than the logic required to manipulate them.
What is encapsulation? - ANSWER✔✔-The wrapping up of data and functions into a
single unit (called class) is known as encapsulation.
Encapsulation containing and hiding information about an object, such as internal data
structures and code.
Define inheritance? - ANSWER✔✔-Inheritance is the process by which objects of one
class acquire properties of objects of another class.
It allows the extension and reuse of existing code without having to rewrite the code
from scratch.
Define polymorphism? - ANSWER✔✔-Polymorphism simply means "many forms". In
java polymorphism is acheived through method overloading and overriding.
For example, say you have an Animal class and two sub classes called Lion and Cat
class. All animals make a sound, so lets say there is a make sound method in all of these
classes.
,When you call the make sound method from a lion object that is stored in an Animal
reference, it would call the make sound method from the Lion Class. That is how you
would explain polymorphism using overriding.
Define Constructors? - ANSWER✔✔-A constructor is a member method with the same
name as its class. The constructor is invoked whenever an object of its associated class is
created.It is called constructor because it constructs the values of data members of the
class.
What is a Class? - ANSWER✔✔-A class is a blueprint for an object
What is an Object? - ANSWER✔✔-An instance of a class
What is multiple inheritance? - ANSWER✔✔-A class can inherit properties from more
than one class which is known as multiple inheritance.
What are the advantages of inheritance? - ANSWER✔✔-Code reusability
Saves time in program development.
What is the difference between an Array and a List? - ANSWER✔✔-The main difference
between an array and a list is how they internally store the data. whereas Array is
collection of homogeneous elements. List is collection of heterogeneous elements.
, What is an iterator? - ANSWER✔✔-Iterators are like pointers. They are used to access
the elements of containers thus providing a link between algorithms and containers.
Iterators are defined for specific containers and used as arguments to algorithms.
What is this pointer? - ANSWER✔✔-It is a pointer that points to the current object. This
can be used to access the members of the current object with the help of the arrow
operator.
What are pass by reference and passby value? - ANSWER✔✔-Pass By Reference means
the passing the address itself rather than passing the value.
Passby Value means passing a copy of the value to be passed.
What is the Java API? - ANSWER✔✔-What is the Java API?
The Java API is a large collection of ready-made software components that provide
many useful capabilities, such as graphical user interface (GUI) widgets.
What is the Java Virtual Machine (JVM)? - ANSWER✔✔-The Java Virtual Machine is
software that can be ported onto various hardware-based platforms.
What is variables and then types - ANSWER✔✔-Variables is an identifier that denotes a
storage location used to store a data values.unlike constants that remain unchanged
during the execution of a program, a variable may takes different values at different
times during the execution of the program.
